JPH0421397A - Step-motor driver - Google Patents

Abstract

PURPOSE:To relieve software burden on a controller while reducing the size and cost of cable, connector or the like by operating a power supply connecting means based on a drive signal created from each switching signal in place of a drive signal. CONSTITUTION:A signal variation detecting circuit 30A receives a phase A switching signal and a lagged signal (a) at an element 31 and produces a variation signal DTC.A. Subsequently, an OR gate 33 produces a trigger signal S. Consequently, a drive signal generating means 40 produces a drive signal IDRV having preset duration Td. A power supply connecting means, i.e., a transistor 21, is driven by the drive signal IDRV produced in a unit 20 and connects a step motor 10 with a drive source. Upon settlement of the phase A switching signal, the drive signal IDRV disappears upon elapse of the time Td thus turning OFF the transistor 21.

Description

[Detailed description of the invention] “Industrial Application Fields” The present invention relates to a stepping motor drive device.

[Prior Art 1] Stepping motors are widely used because they have advantages such as quantitative drive performance, ease of speed switching, and hold torque retention.

An example of such a stepping motor driving device (20) is shown in FIG.

In the figure, IOA to 10D are stepping motors 10
Each phase winding is connected to a drive power source via a common transistor 21 (diode 22) serving as a power supply connection means and individual transistors 25A (25B to 25D... not shown) serving as a current-carrying connection means. .

In addition, 24A (24B to 24D...not shown) is
A commutating diode is connected in parallel to the phase winding ALOA (IOB to 10D), and 23 is a diode interposed between it and the hold power supply.

Then, the transistor 21 is turned off by the drive signal DRV.
The transistor 25A is turned ON by the switching signal A phase.
N is given. Therefore, as shown in FIG. 4 illustrating the case of the two-phase excitation drive force type, if the excitation phase is switched in the order of transistors 25A, 25'B, 25C, and 25D under the transistor 21 being ON, the stepping motor can be activated. 10 can be rotated in the forward direction, and by reversing the excitation order, it can be rotated in the reverse direction. Further, the rotation speed is regulated by the frequency of the switching signal (A to D phases).

Furthermore, in order to stop the stepping motor 10, it is preferable to leave it in the excitation state (A phase, D phase) at time t1 in FIG. At this time, the drive signal DRV becomes low level, the transistor 21 is turned off, and a predetermined hold current is supplied to the stepping motor 10 from the low voltage hold power supply.

Therefore, it is possible to save power and prevent motor overheating.

Here, the drive signal DRV for controlling the rotation of the stepping motor 10 and the switching signals A-phase to D-phase are determined by the control system [100] of the entire device that employs this as a power source, at a timing according to its purpose, entered in mode.

For example, when used as a power source for the print head feeding mechanism of a printer, the C
The control device 100 including the PU etc. outputs each signal DRV, phase A to phase D, which has been subjected to software processing and is adapted to the printing mode.

[Problem to be solved by the invention] By the way, the stepping motor 1 limited to the above printer
0 driving device 20 is becoming more and more multi-functional, and on the other hand, there is also a strong demand for smaller size, lighter weight, and lower cost. Therefore, from the perspective of the entire device, the driving device 20, which is a part of the component, is becoming more and more multifunctional. I want to reduce the software processing burden related to this.

In addition, when constructing equipment, there is a basic requirement to reduce the number of various signals, such as reducing the number of core wires of flexible cables that connect between This is to promote

SUMMARY OF THE INVENTION An object of the present invention is to provide a stepping motor drive device that can reduce the size and cost of cables, connectors, etc., and reduce the software processing burden on a control device.

[Means for Solving the Problems] The present invention focuses on the timing of the drive signal and each switching signal, the mechanical follow-up characteristics of the stepping motor, etc., and is configured to generate the drive signal from the input switching signal. It accomplishes its purpose.

That is, the present invention includes a power supply connection means for connecting each phase winding of a stepping motor to a drive power supply based on a drive signal, and a means for supplying a drive S to the phase winding based on a switching signal for each phase. Trigger signal generation for outputting a trigger signal each time each of the switching signals is inputted, in a stepping motor driving device including a connecting means and configured to rotationally drive the stepping motor by shifting the phase of each switching signal. and a retriggerable drive signal generating means for outputting a drive signal of a set time length each time a trigger signal is manually applied, and the drive signal generated from each of the switching signals is used instead of the drive signal to generate the drive signal. The present invention is characterized in that it is configured to operate the power supply connection means.

1 Effect J According to the present invention, the trigger signal generating means outputs a trigger signal every time each switching signal is input.

Then, each time the trigger signal is input, the drive signal generating means is re-triggered and outputs a drive signal of the set time length.

Here, a drive signal generated within the device operates the power supply connection means to rotationally drive the stepping motor. Therefore, the rotation can be controlled using only the number of switching signals corresponding to the number of phases of the stepping motor, and the burden of processing the drive signal generation software of the conventional control device can be eliminated. Furthermore, the number of cable cores related to drive signals can be reduced.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the overall configuration.
0 is provided with a trigger signal generating means 30 and a drive signal generating means 4o, and a transistor 21 serving as a power supply connecting means.
The drive signal IDRV'tON generated in the device 20
- It is configured to be driven in the OFF state. That is, as is clear from the comparison with the conventional example shown in FIG. 3, the control device 100 outputs only the phase switching signals A to D phases.

First, the trigger signal generating means 30 includes a number of signal change detection circuits IN30A to 30D equal to the number of phases of the stepping motor 10 (four phases in this embodiment), and each detection signal DTC-A to DTC-D.
Each of the six signal change detection circuits 30A (30830C, 30D) is formed from an OR gate 33 that generates and outputs a trigger signal S by receiving TC-D as an input, and each of the six signal change detection circuits 30A (30830C, 30D) is made up of an exclusive OR element 31 and a delay circuit 32, Changes in the switching signal are detected from the signal A phase (B phase, C phase, D phase) and this delayed signal a.

On the other hand, the drive signal generating means 40 is formed from a retriggerable monostable multivibrator, and the time length of the output signal (drive signal IDRV>) is determined by the time constant of the capacitor C and the resistor R. This time constant is set. Can be changed.

Therefore, the trigger signal generating means 30 generates a trigger signal S when the input of any of the switching signals A to D changes.
is output, and the drive signal generating means 40 outputs a trigger signal S.
It is possible to output a drive signal IDRV of a set time length that is retriggered each time a drive signal IDRV is input.

Next, the operation of this embodiment will be explained with reference to FIGS. 1 and 2.

In FIG. 2 (only phase A is shown), phase A changes from a high level hold state to a low level. In other words,
As shown in FIG. 4 above, when the phase is subsequently switched in the order of B phase, C phase, and D phase, and the stepping motor 10 is in the starting state of being rotationally driven, the element 31 of the signal change detection circuit 30A
The switching signal A phase and the delayed signal a are inputted to the input terminal 1, and a change signal DTC-A is thereby outputted. Subsequently, the OR gate 33 outputs the trigger signal S.

Then, the drive signal generating means 40 outputs a drive signal IDRV having a preset time length Td. Therefore, if any of the switching signals A to D phases changes within the time length Td, the drive signal IDRV remains output.

Here, the transistor 21 serving as a power supply connection means is driven by a drive signal I DRV generated within the device 20 that is isometric to the drive signal DRV, instead of the drive signal DRV output from the conventional control device f100. , connect a driving power source to the stepping motor 1o.

Therefore, the stepping motor 10 is rotated in a predetermined direction at a predetermined speed based on the switching order and switching speed of the switching signals A to D phases.

Then, as shown in FIG. 2, when the switching signal A phase stops changing (more specifically, the B to D phases also do not change), the drive signal IDR■ disappears after the elapse of time Td, and the transistor 21 turns OFF. be done.

Therefore, the A-phase winding fill OA is supplied with low voltage power from the hold power supply, and the stepping motor 1o is placed in the hold state.

According to this embodiment, the trigger signal generating means 3
0 and a drive signal generating means 4o, the power supply connecting means (21) is operated by the drive signal IDRV generated within the device 20 by detecting signal changes of the externally inputted switching signals A to D phases. Because there is, the control device 100
This drive system can wipe out the software processing burden related to the drive signal DRV, etc., and can reduce the number of gable cores connecting both 20.100. It is possible to achieve a reduction in the size and cost of the entire device that employs 20.

Further, the trigger signal generating means 30 generates a signal from the phase winding 1°A to IO.
Since the configuration includes the same number of signal change detection circuits 30A to 30D as the number of signal change detection circuits 30A to 30D, stable driving can be achieved that can follow even higher switching speeds of the switching signals A to D phases, that is, even higher rotational speeds of the stepping motor 10. is guaranteed.

Furthermore, since the drive signal IDRV for driving the transistor 21 serving as the power supply connection means is generated by each switching signal, the motor 10 is necessarily disconnected from the high-voltage drive power supply during a hold state in which the switching signal does not change.

In other words, according to the conventional example, a malfunction occurs in which the transistor 21 is turned on even in the hold state due to a software problem, but according to the present invention, this can be completely avoided. Prevents overheating. In other words, these components 1
It is possible to reduce the capacity to 0.21, etc.

C Effect of the Invention 1 According to the present invention, a trigger signal generating means and a drive signal generating means are provided, and the power supply connecting means is
Since the device is configured to be driven, it is possible to significantly reduce the software processing burden on devices such as printers that employ this device, and it also greatly contributes to achieving downsizing and cost reduction of the device as a whole.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a timing chart for explaining the operation, and FIG.
The figure is a block diagram showing a conventional example, and FIG. 4 is a timing chart for explaining the operation of the conventional example. DESCRIPTION OF SYMBOLS 10... Stepping motor, 10A-10D... Phase winding, 20... Drive device, 21... Transistor (source connection means), 25A-2
5D... Transistor (current connection means), 30... Trigger signal generation means, 30A to 30D... Signal change detection circuit, 33... OR gate, 40... Drive signal generation means, A phase to D Phase: Switching signal, S: Trigger signal, ■DRV: Drive signal, DRV: Drive signal.

Claims (1)

[Claims] (1) Includes a power supply connection means that connects each phase winding of the stepping motor to a drive power source based on a drive signal, and an energization connection means that causes a drive current to flow through the phase winding based on a switching signal for each phase. , a stepping motor driving device formed to rotationally drive a stepping motor by shifting the phase of each switching signal, comprising: a trigger signal generating means for outputting a trigger signal each time each switching signal is input; and a trigger signal. retriggerable drive signal generation means for outputting a drive signal of a set time length each time the drive signal is input, and the power supply connection means is operated by the drive signal generated from each of the switching signals instead of the drive signal. 1. A stepping motor drive device, characterized in that it is configured to